Gusseted bags



April 28, 1970 AKlo sAlTo ETAL 3,508,701

GUSSETED BAGS Filed Sept. 24, 1968 2 Sheets-Sheet 1 ,Q4/fa .5H/70 M yam/o 1mm/1 MLA/na! JWN-M,

Ap'l 28, 1970 AKlo SAITO ET A1. 3,508,701

GUSSETED BAGS Filed Sept. 24, 1968 2 Sheets-Sheet z ,qm 5mn fw )las/m MMS/M070 INVENTORS v/uw,

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United States Patent O Int. ci. Brsd 31/10 U.S. Cl. 229-53 4 Claims ABSTRACT OF THE DISCLOSURE A gusseted bag fabricated in a single gluing step from a blank. The end portion of the front panel of the bag, the lrear panel of the bag and the panels of the gussets are 1n stepped relationship, and the edges of the respective panels which are at right angles to each other are Joined by an oblique edge portion so that the edge portions join each other at outside angles greater than 90.

This invention relates to improvements in gusseted bags fabricated by one pasting step from paper or the similar lilnd of flexible sheet material, such as synthetic resin In the conventional gusseted bags fabricated by one adherlng step, that is, in the bags fabricated such that both sides thereof are provided respectively with a gusset so as to form the side walls of the bag and also to form approximately a hexahedron when lled with the packaged material, the most typical construction of the opening portion at the top and the base portion is made such that the end portion of the opposing surface of each of said gussets is stepped up to the right or left side viewing from the crease line of each of said gussets and that there is the end portion of one of the bag surface at the upper position of said stepped portion, and if said one of the bag surface is the front surface of the bag, the end portion of the other of the bag surface, namely of the rear surface of the bag, is stepped down with respect to the end portion fo the front surface thereof so as to form the stepped portions as a whole.

Due to the above-mentioned construction, the opening portion of the bag in which said gussets are folded inwardly along each crease line appears in the stepped form on one surface without completely overlapping among the end portion of the front surface of the bag,

each end portion of the two opposing surfaces of the respective folded gussets, and the end portion of the rear surfaces of the bag, that is, in the state of these portions being respectively slipped out somewhat, and accordingly glue is applied to said opening portion formed by said slipped portions and then said opening portion is folded at the neighbourhood of the end portion of the rear surface of the bag and preferably along the inside thereof somehwat thereby to bond the front surface portion and the rear surface portion of the bag together, and thus the closure of said opening portion can be completed.

According to the method of such closure, one pasting step is possible and also the closure can be made securely with a large strength and consequently not only the work for manufacturing bags but also the work for filling the bag with packaged material have been able to be remarkably rationalized.

However, in the bags of the aforesaid type, the stepped portion having approximately right angle is formed respectively in the boundary lines between the front surface portion of the bag and one surface of the gusset, between the opposing surfaces of the gusset, and between one surface of the gusset and the rear surface portion of the bag,

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so that there is an apprehension that the strength of a bag blank is lowered in the respective boundary line. Further, since either one of the corner portions in the opposing surface of the gusset is especially in the sharp form of right angle, the bonded corner portion is liable to be peeled therefrom and consequently the closure strength of the bag is lowered.

These disadvantages are brought basing on the fact that the respective end portion of the front surface p0rtion of the bag is in the completely stepped form having a right angle.

Accordingly, it is the primary object of this invention to provide a bag having the construction such that in the bag in which the respective end portion of the front surface portion of the bag, the opposing surface of gussets and the rear surface portion of the bag are in the stepped form, a part or all of the corner portions of the respective end portions contiguous to each other are revised respectively to the angle exceeding It is another object of this invention to provide a bag formed by cutting off some part of the corner portions which are in the sharp form at the angle of 90 as the concrete means of revision of corner portions.

It is still another object of this invention to provide a multi-ply bag in 4which several pieces of the bag blank, each having the different area of cut-off part in the corner portions as the concrete means of such revision thereof, are combined.

It is a further object of this invention to provide a multi-ply bag in which the bag blank having the aforesaid revised portion of said corner portion is combined with the bag blank having non-revised portion of the same.

According to the above-mentioned characteristic features of this invention, as a part or all of the corner portions of the respective end portions contiguous to each other of the front surface portion of the bag, the opposing surfaces of gussets and the rear surface portions of the bag are revised respectively to the angle exceeding 90, the apprehension for lowering of strength of the bag from said corner portions in the direction of boundary lines is greatly decreased.

In the same way, as the sharp portion of approximately right angle in each of the opposing end portions of the gussets is particularly revised, the apprehension for peeling off from said portion is overcome and the closure strength is increased.

Further, in the bag as in this invention, the cutting in the stepped form of the aforesaid bag blank is in general carried out by putting the seam of the same stepped form on said bag blank and then by separating the seamed portion in the longitudinal direction, and according to this invention, there is a further advantage such that the totally extended length of said seam for cutting is more shortened.

Furthermore, in case of carrying out the work for revising the corner portions of the stepped portions in this invention, that is to say, the work for cutting off the corner portions, there is no technical trouble in the bag manufacture of this kind.

Other additional features and advantages of this invention will become apparent from the following detailed descriptions of the embodiments of this invention Without limitation of these descriptions, taken with the accompanying drawings in which:

FIG. 1 shows a perspective view of a partial development of one of the most preferable embodiments of the bags according to this invention;

FIGS. 2, 3 and 4 are respectively schematic views showing only the necessary parts in several other embodiments of this invention, that is, FIG. 2 is a schematic View in which the end portion of a gusset has been re- 3 vised by an oblique line; FIG. 3 is a schematic view in which only the edge of the surface of either one of the gussets has been revised by an oblique line; FIG. 4 is a schematic view in which the edges of both surfaces of the gusset have been revised in the same way as shown in FIG. 3;

FIG. 5 is a schematic view of other modications in the combination of two kinds of revised bag blanks;

FIGS. 6a and 6b are schematic views of further modifications in the combination of non-revised bag blanks and revised bag blanks; and

FIG. 7 is a schematic view of the preferable modificafication of the moditication as shown in FIG. 2.

Referring to FIG. l, let it be assumed that the portion of one surface edge in the uppermost position of the opening of the bag 1 is designated as a front surface portion 2, the edge of the other surface portion is in the lowermost position and designated as a rear surface portion 3, and the edges of the opposed surfaces 4, 5 of gusset are disposed therebetween in the stepped form. In the conventional bags, as already described above, the respective edges of the front surface portion 2 of the bag, the opposing surfaces of gussets 4, 5, and of the rear surface portion 3 of the bag are crossed approximately at right angle in the line connecting their edges at their contiguous positions, thereby to form the corner portions of approximately right angle at these portions.

In the embodiment of FIG. 1, as shown in the right hand of the drawing, the `corner portion from the front surface portion 2 to the rst surface 4 of the gusset is cut oif along an oblique line 6, thereby to revise said corner portion between the second surface 5 of the gusset 7, 8 exceeding 90 at least, and in the same manner the corner portion between the second suface of the gusset and the rear surface portion 3 of the bag is revised along an oblique line 9 thereby to form two corner portions 10, 11 exceeding 90.

The condition of the bag wherein the bag blank revised in such a manner as above is formed in a tubular form and the gusset is folded as shown in the right hand of the drawing. As will be clear from this condition, there is no corner portion having approximately sharp angle of 90 by revising said corner portion, and at the same time the exposed area of the first surface 4 of the gusset increases and accordingly the adhesive bearing portion becomes large.

Consequently, the configuration of the closed opening portion of the bag such that the opening portion was folded along a folding line 12 and adhered with glue becomes more strong than the conventional bags. The configuration of the opening portion of the bag is as mentioned above, but the other end portion of the bag, namely the base portion thereof has somewhat different form, for the reason that the bag blank is cut off continuously from, for example, a lengthy coil 13.

However, in the base portion also, the corresponding corner portion is revised along the oblique lines 14, 15 corresponding to the aforesaid oblique lines 6, 9 and also in the case that the base portion is folded, the bonding area increases due to the oblique line 15, as shown in a. Further, the leakage from the corner portion in the case of the base portion along a fold line 16 can be prevented by the oblique line 14, as shown in b, these being ad-V vantages of this invention.

It goes without saying that the fold lines 12, 16 in the case of the said opening portion or base portion of the bag being closed are not limited to the above-mentioned illustration.

That is to say, in the case of use for the materials, for example, granular materials which do not ocur leakage of the contents of the packaged materials, the position of the fold line 12 may be substituted by the position of 12 which is an edge line of the rear surface portion 3 of the bag. In this case, the number of the ply to be folded is decreased and the folding work becomes easier.

On the other hand, in the base portion of the bag in the above embodiment the b portion is formed by the oblique line 14 and can prevent almost completely the leakage of the packaged material. Further, in the same way as mentioned above, it is easier to put the fold line at the position of 16 in place of the fold line 16.

The selection of the position of the fold line for closure of the opening portion of the bag can be applied, as occasion demands in addition to the above-mentioned embodiment of this invention, to the other embodiments described in the following. Further, the above embodiment can be of course applied to the two ply or three ply bags according to the necessity.

Nextly, several other embodiments of this invention are shown, but the illustration for the parts which can be referred to the above-mentioned embodiment has been omitted therein.

Referring to FIG. 2, there is shown the edges of the opposing surfaces 20, 21 of the gusset, said edges having been revised in such a manner as mentioned above so that the oblique line of said edges may form a straight line in one direction. According to the above embodiment, the crease line 23 of the gusset is extended from the vicinity of the middle of said oblique line 22 to the longitudinal direction of the bag, so that in the case of folding said gusset at said crease line, as shown in the right hand of the drawing, the edge of the opposing surfaces 20, 21 of said gusset appear in the shape of a letter V laid down in the side and thus the bonding area of said edges increases. When said edges have such shape, there is the advantage that the shape of the opening portion of the bag becomes just same as that of the base portion of the bag.

Referring to FIG. 3, the edge of one opposing surface 30 of the gusset forms a horizontal line and the edge of the other opposing surface thereof forms an oblique line 32 which is inclined in one direction. In the case that the gusset is folded in the same way as mentioned above, said oblique line 32 revises the corner portion of said opposing surface, and at the same time only the c portion of the other opposing surface of the gusset appears.

Referring to FIG. 4, the corner portion of each of both opposing surfaces 40, 41 of the gusset is respectively revised by oblique lines 42, 43 which is the modified embodiment of this invention. There is left a straight line portion between the oblique lines 42 and 43, and from the middle of said straight line a crease line of the gusset is extended longitudinally. Accordingly, in the case of folding the gusset at said crease line, as shown in the right hand of the drawing, the first surface portion 40 of the gusset appears in the shape of a letter V laid down on the side, as shown with the d portion.

Referring to FIG. 5, there is shown the combination of two ply blanks of the bag which are respectively revised in their corner portions in the same way as in the embodiment of FIG. l. The oblique lines 50, 50' or 51, 51 in the revised corner portions are overlapped in the slightly slipped state and also in the state such that the front surface portion of the bag and the back surface portion thereof are slipped in the same degree. In the case of folding the gusset with this blank, as shown in the right hand of the drawing, the respective edges ofthe combined ply blanks appear in proportion to the slipping degree of said oblique lines 50, 50 or 51, 51', as shown with e and f portions, and thus the closure strength becomes larger.

Further, referring to FIG. 6, there is shown the embodiment in the combination of the corner portion revised as in this invention and the non-revised corner portion.

In the embodiment of FIG. 6a, the non-revised ply 61 and the revised ply 62 are combined as shown in the drawing. In said revised ply the revision is made at two positions of the opposing surfaces 63 and 64 of the gusset, and in the middle of the revised oblique line 65, 6'5' the stepped vertical line of the non-revised ply 61 is positioned. Some slipped portion 66 is respectively taken in the lower edge lines in advance.

According to the combination in suc-h a manner, there is formed an exposed portion g corresponding to a rightangled triangle in proportion to the length of said revised oblique line 65, 65 on the opposing surfaces of the gusset of the bag.

Further, in the embodiment of FIG. 6b, the revised oblique line of the revised ply 62h corresponding to the aforesaid revised ply 62 makes one oblique line 65h, which forms an exposed portion g having a shape of V-letter on the opposing surfaces of the gusset by folding at the middle thereof. In this case, the edge line of nonrevised ply 61 appears on the position in which said exposed portion g is divided into two parts.

As will be clear from the above-mentioned two preferable embodiments, the bonding strength of the bag increases remarkably by combining the revised ply with the non-revised ply. According to such combinations as mentioned above, various kinds of modiiications can be thought out.

For example, by making the edge of each of the opposing surfaces in the FIG. 2 a straight oblique line, such a combination that only the end portion of the front surface portion and the rear surface portion of the bag are placed in the slipped position somewhat and that said oblique lines are just same as those in FIG. 2 can 4bf? thought out as shown in FIG. 7. This embodiment has also just same configuration in the opening portion and the base portion of the bag. These oblique lines may be shaped in slightly curved lines.

As mentioned above, the essential points of this invention consist in that the corner portion of the bag blank in the end portion of each of the front surface portion or the rear surface portion of the bag or the gusset provided therebetween is revised to the angle exceeding 90; such revision can be made by, for example, cutting off or partially cutting the bag blank; and that as other modiiications of this invention, conventional bag blanks which are not revised in corner portions can be variously combined.

While this invention has been described in the preferred embodiments, the concrete means for revising the corner portions or the means for combining with the nonrevised blank of the bag is not limited to only the abovementioned embodiments, and various modications can be made therein without departing from the spirit of the invention and in particular from the scope of this invention.

What is claimed is:

1. In a gusseted bag fabricated by a single pasting step from a blank in which the respective end portions of the front surface portion, the rear surface portion, and the opposing surfaces of the gussets therebetween are parallel, stepped and successively joined by perpendicular edge surfaces to thereby form corners, the improvement wherein at lease one of said corners is cut off to form an angle greater than with its respective perpendicular edge surface.

2. In the gusseted bag according to claim 1, wherein said angle greater than 90 is formed by cutting along an oblique line connecting the perpendicular edge surfaces between said front surface portion and one gusset and between said rear surface portion and the other gusset, respectively.

3. In the gusseted bag according to claim 1, wherein said blank having said corner revised is combined with a blank without a revised corner, to thereby form a twoply bag.

4. In the gusseted bag according to claim 1, wherein both of said corners are cut off to form angles greater than 90 with the respective perpendicular edge surfaces.

References Cited UNITED STATES PATENTS 426,607 4/1890 Single 229-58 FOREIGN PATENTS 766,127 8/1967 Canada.

DAVID M. BOCKENEK, Primary Examiner U.S. Cl. X.R. 229-57 

